Rheumatic heart disease refers to a group of heart disorders that develop as a complication of rheumatic fever. It is one of the most common heart disease in children, particularly in developing countries.
Rheumatic fever is the antecedent of rheumatic heart disease. As per the Jones criteria, rheumatic heart disease will have indication of group A streptococcal infection, with one or two major diagnostic criteria, and two minor ones . The major diagnostic manifestations are
Minor manifestations of the disease are fever, arthralgia, long PR interval, and elevated acute phase reactant, elevated levels of leucocytes and presence of C-reactive protein.
In some patients, difficulty in breathing, exercise intolerance, and a rapid heart rate may indicate rheumatic heart disease.
Streptococcal infection is confirmed by measuring anti-streptococcal antibody levels which tend to be elevated. This is important especially in those patients who have chorea as the only major diagnostic manifestation. Rapid antigen detection test is used in the diagnosis of streptococcal pharyngitis. This along with throat culture are confirmatory tests for streptococcal infection, which is an antecedent for rheumatic heart disease. Inflammation brings about an increase in the levels of C-reactive protein and ESR and this is used to check for recurrence and also to monitor inflammation.
Chest radiography helps to differentiate symptoms of heart failure from that of rheumatic disorders. It helps to diagnose manifestations like cardiomegaly and pulmonary congestion. Valve disorders and ventricular dysfunction are diagnosed with echocardiography. This imaging technique help in better diagnosis of the condition when compared to clinical findings alone . It is also used in monitoring the progression of valve stenosis and may be useful in deciding its best treatment modality. Electrocardiography was found to be 92% specific in the diagnosis of rheumatic heart disease . Mitral and aortic valve diseases are assessed by using heart catheterization. Some patients may show first degree atrioventricular block indicated by the prolongation of PR interval in ECG.
Histological tests help to reveal the presence of lesions on valves at the line of closure. Presence of Aschoff bodies or nodules of scar tissue can be noted in the pericardium. Microscopic examination of the affected valve show presence of thrombi and inflammation. Chronic form of rheumatic heart disease may have neovascularization and calcification in the different wall layers . Immunohistochemistry tests may reveal the presence of elevated levels of CD4 and CD8 T-cells.
Preventing rheumatic fever due to group A streptococcal infection is often the first line of treatment. In patients who have already developed rheumatic heart disease, treatment focuses on treating streptococcal infection, suppressing inflammation of tissues, and treatment of congestive heart failure. This is followed by treatment to prevent recurrent rheumatic heart disease and associated complications. Streptococcal infection is treated with oral penicillin, ampicillin or amoxicillin. For those who are allergic to penicillin, erythromycin or first generation cephalosporin is recommended.
Inflammatory manifestations of the disease are controlled using salicylates and steroids. Aspirin is the most common medication suggested for improving inflammatory response, except in those patients with chorea. Once the symptoms improve, aspirin dose is gradually reduced. Phenobarbital and diazepam are useful in chorea, which often resolves on its own without any specific treatment. Oral prednisone is useful in patients with severe form of carditis, characterized by cardiomegaly and congestive heart failure. Depending on the severity of symptoms, oral prednisone may be continued for two to six weeks. Digoxin and diuretics are recommended for patients with acute rheumatic fever. In valve insufficiency, cardiac output can be improved using ACE inhibitors.
Further damage to the valves should be prevented in case of acute rheumatic heart disease. Benzathine penicillin G intramuscular injections are the first line of prophylaxis treatment for the patients. This dose is given every four weeks and is continued for 5 years in patients with rheumatic fever without carditis . Those with rheumatic fever and carditis, but without any symptoms of valve disorder, are recommended antibiotic treatment for 10 years.
Surgery is recommended in patients who show persisting symptoms even after treatment for acute rheumatic heart disease. This will in help in improving the functioning of the valves. Mitral valvulotomy, balloon valvuloplasty or mitral valve replacement are suggested in these cases. Some patients may require neurology and/or cardiothoracic consultation depending on the complications.
Mortality rate for rheumatic heart disease ranges from 1.8 in the US to 7.6 in the developing regions of South East Asia. Progress of the disease differs in different individuals. Prognosis often depends on the involvement of heart. The favorable factors for good prognosis in patients with mitral valve disease include little or no mitral valve regurgitation and absence of aortic valve lesion. But patients who have had more than one attack of rheumatic fever, with aortic or tricuspid lesion and atrial fibrillation might not have good prognosis. Those with mitral valve prolapse do not have good outcome even with surgical repair. This is due to scarring in leaflets and chords. In many case scarring remains progressive even with surgery. Good cardiac muscle functioning and incompetence without stenosis are very favorable for good prognosis in patients with aortic valve disease. But stenosis combined with incompetence and left ventricular hypertrophy are poor prognostic factors in aortic valve disease. In most of the cases the disease progresses step by step.
Group A streptococcal infection is thought to trigger an autoimmune response after 2-3 weeks of onset of pharyngitis . This autoimmune reaction, which includes both cellular- and humoral-mediated immunity, is considered to be the cause of rheumatic heart disease. Streptococcal invasion of the upper respiratory epithelial cells results in symptoms of pharyngitis including sore throat, fever, headache and an increase in serum leukocyte levels. After few weeks from the onset of the condition, the infectious organism incites an acute inflammatory response, characteristic of rheumatic heart disease. Only infection of pharynx by the bacteria is found to cause this condition. Certain populations are found to be more susceptible to develop rheumatic heart disease with streptococcal infections . This shows the probable presence of a genetic factor that increases the risk of this disease. A human leukocyte antigen (HLA) subtype DR (HLA-DR) is also known to be associated with the development of rheumatic heart disease .
Incidence of this disease reduced considerably by 20th century in the developed countries and is now in the range of one in 100,000 persons . But in developing countries, this disease still has a higher incidence. Streptococcal pharyngitis is one of the most common etiological factor for this condition. Incidence of streptococcal infection may vary between countries and even within the same country. About 282,000 new cases of rheumatic heart disease are reported in the world every year .
It is a major reason for concern among children and young adults in developing countries, as it is most commonly seen in the age group of 5-15 years. Streptococcal pharyngitis is not common among children below the age of three years. A higher incidence of the disease is reported among Native Hawaiian and Maori population. Rate of incidence of rheumatic heart disease is found to be equal among men and women, but outcome is found to be better for men when compared to women. The median age for the occurrence of this disease is around 10 years, although it may also occur in some adults above the age of 25 years.
Rheumatic heart disease occurs in 39% of the patients with rheumatic fever. It is also associated with poverty. Poverty is related to poor housing and overcrowding, two factors that favor the spread of streptococcal infection among the inmates. Poverty also lead to lack of proper healthcare and under-nutrition, both of which may lead to complications associated with streptococcal infection.
The actual pathogenesis of the disease is not fully understood yet. It is known that streptococcal pharyngitis and rheumatic fever are associated with rheumatic heart disease. One of the theories suggest that antibodies against the bacteria trigger a type II cytotoxic hypersensitivity reaction . The cardiac and smooth muscle cells of the body are mostly affected as they have elements which are structurally similar to bacteria. This leads to the immune-mediated inflammatory condition - rheumatic fever. All major valves of the heart, including the mitral and aortic valves, are affected by the autoimmune response that develops after the infection. In acute form of rheumatic disease small thrombi develop in the valves, while in chronic condition valves might undergo thickening and fibrosis.
As cardiac cells are the most affected, it leads to pancarditis characterized by inflammation of all three cardiac layers – endocardium, myocardium and pericardium. In about half of the patients, carditis may occur. Pericarditis usually ensues in about 10% of the patients.
Rheumatic heart disease refers to a group of heart disorders that develop as a response to group A streptococci infection. The actual pathogenesis of the disease is not fully defined yet. The autoimmune reaction triggered by the infection result in cardiac inflammation and scarring. Rheumatic heart disease may be acute or chronic, and both the conditions lead to many complications. It is more prevalent in children in the age group of 5-15 years, particularly in developing countries including sub-Saharan Africa, south-central Asia, and also among the indigenous populations in Australia and New Zealand. It is common in regions where pharyngitis is not treated completely, either due to lack of compliance on the patient’s side or due to non-availability of antibiotics . Rheumatic heart disease can be prevented by treating streptococcal infection. Mortality rate associated with the disease is about 1-10%.
Rheumatic heart disease refers to a group of inflammatory heart disorders that develop from rheumatic fever. This condition is very common among children in the age group of 5-15 years, particularly in developing countries. Rheumatic fever is caused by the infection of the bacteria streptococci.
Rheumatic fever affects heart, joints and the central nervous system. When left untreated, it may lead to valve damage, and thus, heart failure and death. Poverty increases the risk of developing this condition as it leads to poor housing and overcrowding. Lack of access to healthcare and availability of antibiotics also are important risk factors for rheumatic heart disease.
Rheumatic heart disease may not have always obvious symptoms. The most common symptoms of the condition include palpitations, chest pain, breathlessness, swelling of joints, fever, muscle pain, increased heart rate and rashes on torso. Diagnosis of the disease is done using a complete medical examination, imaging techniques, and medical history. Presence of past streptococcal infection is indicative of rheumatic heart disease if appropriate symptoms are present. Enlargement of heart is checked using echocardiogram and chest X-ray. Echocardiograms also help in identifying the structure of valves. Changes in the normal rhythm of the heart can be checked using ECG.
Treatment of rheumatic heart disease depends on the severity of the symptoms. Antibiotics are the first line of treatment to control streptococcal infection. Inflammation is controlled using medications like aspirin. Steroids may be recommended for those who have congestive heart failure. Treatment may be continued for 5 – 10 years depending on the risk of recurrence. Surgery is suggested if there is no improvement in symptoms even after standard treatment. Diagnosis and treatment of strep throat is the most important method to prevent rheumatic heart disease. Once diagnosed, infection should be treated to prevent further complications.